The two, both aged 36, became billionaires when the company they founded, software maker Atlassian, listed on the NASDAQ in the US late last year.

The pair have topped the Young Rich list five times, jointly taking out the number 1 spot every year since 2012.

The combined wealth of the 100 members of the 2016 BRW Young Rich list has risen, with a booming property sector and technology market, to a record $12.3 billion, up from $10.6 billion last year.

Here are the rest of the top 10:

3-4. Dave Greiner, 38, and Ben Richardson, 37, founders of Sydney company Campaign Monitor. They have a combined wealth of $543 million.

5. Perth property developer Paul Blackburne, aged 40. His Blackburne Property Group dominates the Perth apartment market and develops three to four large apartment projects per year. His wealth is $483 million.